Question: Which of the following numbers is a factor of 100? ${3,4,8,9,14}$
Answer: By definition, a factor of a number will divide evenly into that number. We can start by dividing $100$ by each of our answer choices. $100 \div 3 = 33\text{ R }1$ $100 \div 4 = 25$ $100 \div 8 = 12\text{ R }4$ $100 \div 9 = 11\text{ R }1$ $100 \div 14 = 7\text{ R }2$ The only answer choice that divides into $100$ with no remainder is $4$ $ 25$ $4$ $100$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $4$ are contained within the prime factors of $100$ $100 = 2\times2\times5\times5 4 = 2\times2$ Therefore the only factor of $100$ out of our choices is $4$. We can say that $100$ is divisible by $4$.